The present invention relates to a control device of a vehicle provided with a front-seat air conditioner, a rear-seat air conditioner, and an engine to be automatically stopped by idling stop.
An air-conditioning control device for a vehicle comprises a compressor, a cool-air generator including a condenser and an evaporator, and a hot-air generator having a heat source of engine cooling water, and provides conditioning air having a desired temperature by changing the mixture ratio of cool air and hot air with an air mix damper. The conditioning air is supplied into a vehicle compartment by means of a blower fan, and the supply amount of the conditioning air is adjusted by changing a rotational speed of the blower fan. In general, the above-described compressor is driven by an engine, and a water pump to circulate the cooling water is also driven by the engine. Accordingly, when the engine stops, the compressor and the water pump stop, too.
Further, an automatic air conditioner to automatically control an actual temperature inside the vehicle compartment at a target temperature has become the mainstream of the air-conditioning control device for a vehicle. The automatic control of air conditioning is performed based on the environmental conditions inside the vehicle compartment, the environmental conditions outside the vehicle compartment, and parameters representing the air-conditioning operational states set by a passenger (setting of the target temperature inside the vehicle compartment, particularly), whereby the conditioning-air supply temperature, the conditioning-air outlet, the conditioning-air supply amount and others are automatically adjusted.
Meanwhile, many vehicles have recently adopted so-called idling stop in which the engine is automatically stopped when the vehicle stops or travels at a very low speed before the vehicle's stopping in order to improve the fuel economy (gas millage). This idling stop is executed on condition that the preset stop condition is met. This preset stop condition is generally set such that all conditions of a vehicle speed being zero (i.e., the vehicle's stopping), a brake being operated, an accelerator being operated, a shift change being located at a D position, and others are met.
The operation of the air conditioner is generally continued even during the engine's automatic stop by the idling stop from a passenger's comfortability viewpoint. That is, even if the engine is automatically stopped, the air-conditioning control using the cooling function of the evaporator is continuously performed until the temperature of the evaporator increases up to a specified upper-limit temperature, and the air-conditioning control using the heating function of the heater core is continuously performed until the temperature of the heater core decreases to a specified lower-limit temperature. Herein, when the temperature of the evaporator increases over the upper-limit temperature during the cooling, or when the temperature of the heater core decreases below the lower-limit temperature during the heating, the engine is automatically restarted.
In the meantime, some wagon-type or large-sized SUV vehicles have three row seats comprising a first row seat including a driver's seat, a second row seat arranged in back of the first row seat, a third row seat arranged in back of the second row seat. Herein, a space for air conditioning inside the vehicle compartment is so large that an air conditioner for a rear seat (i.e., a rear-seat air conditioner) is generally provided, additionally to an air conditioner for a front seat (i.e., a front-seat air conditioner) of the first row seat.
There is a tendency that the humidity inside the vehicle compartment goes up as the number of passengers increases. Japanese Patent Laid-Open Publication No. 2010-280354 discloses a control in which the operational term of the idling stop is changed according to the number of passengers, and when the humidity inside the vehicle compartment detected by a humidity sensor is high, the opportunity of performing the dehumidification function by the air conditioner is increased so as to attain defogging of windshield glass.
In a case in which both the front-seat air conditioner and the rear-seat air conditioner are separately independent from each other as described above, it may be considered that these both air conditioners are continuously operated during the engine's automatic stop in order to ensure the comfortability for both the front-seat passenger and the rear-seat passenger. In this case, however, the operations of the both air conditioners require a large amount of power consumption.
Accordingly, it may be considered that the operations of the front-seat air conditioner and the rear-seat air conditioner are stopped alternately to reduce the power consumption during the engine's automatic stop. In this case, however, there may be a problem in that the windshield glass is fogged during the heating, in particular. In a case in which the number of passengers is large particularly, the vehicle equipped with its rear seat having a large capacity for passengers may have this problem, in particular.